Gun-sight.



Patented Aug. 28, I900. E. B. TOLMAN.

GUN SIGHT.

(Application filed Aug. 14, 1899.)

2 Shee,ts-Sheet I.

(No Model.)

No. 656,866. 'Pa tented Aug. 28, I900.

- E. B. TOLMAN.

GUN SIGHT. (Application filed Aug. 14, 1899.) I (No Model.) 2 Sheets-Sheet 2.

IIIWIIIIIIII'IIIHII'IIIM IIIIIIIIIIIIA! I 1 \IUVUUVVVVV Nit-En STATES PATENT Cnr'lcin i.

, EDGAR BRCNSONTOLMAN, OF CHICAGO, ILLINOIS.

GUN SIGHT.

SPECIFICATION forming part of Letters Patent No. 656,866, dated August 28, 1900. Application filed August 14, 1899- Serial No 727,206. (No model.)

To ail whomv it may concern;

Be it known that I, EDGAR Bnonson ToL- MAN, of Chicago, in the county of Cook and State of Illinois, have invented certain new and'useful Improvements in Rear Sights for Firearms; and I do hereby declare that the following is a full, clear, and exact description thereof, reference being had to the accompanying drawings, and to the letters of reference marked thereon,which from a part of this specification.

This invention relates tothat class of rear sights for firearms which are located near the breech of .the gun and are raised and lowered to compensate for the fall of the projectile due to gravitation and moved laterally to compensate for the lateral deviations of the projectile occasioned .by the efiect ofwind and by the effect of the revolution of the projectile on its axis and other constant causes due to the gun and projectile and called The main or principal object of my invention is to provide a simple and durable mechanism which is so constructed and arranged that the act of elevation anddepression of the rear sight used to compensate for the effect of gravitation upon the flight of the projectile shall also automatically produce a lateral movement of the sight,which shall compensate for the effect of wind upon the projectile at the range appropriate to each elevation thereof andalso shall compensate for drift and other constant causes which tend to produce a lateral deflection of the projectile. Said mechanism is so constructed that but a single manual adjustment of the mechanism is required to compensate for the effect of a given velocity of wind at any and all elevations of the sight appropriate for different ranges. A permanent mechanical adjustment is made for drift to suit the particular gun on which the sight is used, and such adjustment also answers for each and everyelevation of the rear sight appropriate for different ranges. In this latter respect saidsightinechanisin is like the sight mechanismshown in my prior application for United States Letters Patent, Serial No. G,996,'filed February 27, 1899; but the principle of correcting by a single adjustment for the combined effect of wind and drift is new.

'the projectile dueto effect of wind and that due to drift each describe a substantiallysimilar increasingparabolic curve, so that the lateral adjustment of the sight to coinpensate for both conditions may with almost perfect accuracy be synchronously and automatically effected by the same lateral deflection of the sight which throug'hymy device is effected by its elevation or depression. To adjust the sight for the lateral deviation of the projectile due to wind at point-blank range, it is moved laterally'by a single manual adjustment a distance with respect to the wind-gage scale, which is graduated to rep resent the velocity ofthe Wind per hour, suffi cient to compensate for such velocity. This adjustment remains the same for all elevations of the sight appropriate to different ranges so long as the velocity of the wind remains the same,and the elevation of the sight prod uces the increased lateral deflection of the rear sight appropriate to the effect of the wind at the distance indicated on the elevation-scale. No calculations are therefore required to be made as to effect of wind upon the projectile at the different ranges; but, knowing the velocity of the wind, the marksman merely moves the sight to the point on the wind-gage scale which is appropriate to such velocity, and itremains there until the velocity of the wind changes. It is obvious from the above that it is immaterial whether the wind-gage scale be set at point-blank range or any other range.

I have herein illustrated three dilferent modifications of mechanism for carrying my invention into effect; but it will be obvious that many changes may be made in the details thereof, and I do not wish to be restricted to such details except as made the subject of specific claims.

In the drawings, Figure l is a side elevation of a gun, showing my improved rear sight attached thereto. Fig. 2 is a cross-section, on an enlarged scale, taken through the sight mechanism in an indirectline. Fig. 3 isaside elevation of one side of the sight mechanism, showing the casing which incloses the same in section. Fig. at is a horizontal section, taken through one side of said sight mechanism, on Fig. 5 is a detail section the lines 4 of Fig. 3.

taken on line 5 5 of Fig. 4. Fig. 6 is a rear elevation of the horizontal sight bar, partly broken away to show the manner of attaching a spirit-level thereto. Fig. 7 is across-section of said bar, taken on line 7 7 of Fig. 6. Fig. 8 is a detail of one of the legs which supports said sight-bar. Fig. 9 is a detail view of the casing and one of said legs, showing attached to said casing a wind-gage scale and on said leg an elevation-scale. Fig. 10 is a vertical section taken on line 10 10 of Fig. 9. Fig. 11 is an end elevation of the screw-threaded shaft by which the sight-bar is given lateral movement for compensating for the effect of wind, showing a scale connected with the side wall of the casin g through which the said shaft passes and which is employed as a subdivision of the scale shown in Fig. 9. Fig. 12 is a view similar to Fig. 2, showing a modified form of my invention. Fig. 13 is a side View of the sight mechanism shown in Fig. 12 with the casing thereof shown in section. Fig. 14 is a horizontal section taken on line 14 14: of Fig. 13. Fig. 15 is a horizontal section taken on line 15 15 of Fig. 13. Fig. 16 is a cross-section similar to that shown in Figs. 2 and 12, showing still another modified form of sight mechanism. Figs. 17, 18, and 19 are detail views of a form of supportinglegs used in the sight mechanism shown in Fig. 16.

First referring to the construction shown in Figs. 1 to 11, inclusive, A designates a horizontal sight-bar, which is arranged horizontally over the gun near the breech thereof and provided with an eyepiece 0t, which latter may be provided with any form of sighting-notch or peep. Said horizontal bar A is supported upon legs 13 B, which are pivotally attached at their upper ends to the outer ends of said sight-bar and are each movably connected at its lower end with a casing O,which incloses the sight mechanism on each side of the gun. Said casings O are attached to the side D of the gun by means of screws cflwhich pass through lugs c on the casings. The gun is shown in Fig. 2 and also Figs. 12 and 16 in solid section to avoid the necessity of showing the mechanism contained therein. As herein shown, the lower ends of said legs B are pivotally connected with studs 0, which engage parallel vertical guide-slots c c in the rear walls of the casings O. Said studs are provided on theirinner ends, inside of the legs, with heads 0 and are provided outside of the casings with thumb-nuts 0 which have screwthreaded engagement with said studs. 0 designates a washer on each of said studs between the leg and the inner face of the casing. With this construction said legs may be locked in any position which they may occupy with respect to the slots.

E designates a shaft which passes through and is journaled in the gun-frame and exwith a thu mb-wheel e,by which the shaft may be rotated. Said shaft is provided on each side of the breech-frame, in the part thereof inclosed by the casing O, with a gear section or sleeve E, which is adapted for engage ment with a rack formed on the adjacent leg B and by means of which said legs may be raised as the shaftis rotated. In the present instance the teeth of said rack have the form of cylindric pins 1), which project forwardly from said legs toward the gear-sections E of the shaft E. Said rack-teeth are given this form in order to enable the ,legs to have angular movement with respect to the gear-sections when the legs are being elevated or depressed, as will hereinafter appear.

F designates a guide-loop which is located near the upper end of one of the casings G and with which the adjacent leg B has sliding engagement, as shown more clearly in Fig. 4. Said guide-loop F is adapted to be moved laterally, so as to shift the upper end of the leg laterally, and thereby the sight-barattached thereto. Means for giving lateral movement to said guide-loop consists of a screw-threaded shaft G, which is journaled at one end in the lock-plate D and at its other end in the side wall of the casing O. Said shaft is provided outside of said casing with a thumb-wheel g, by which it may be rotated. Said screw-shaft does not directly engage the guide-loop, but has screw-threaded engagement with a block F, which has swivel connection with the guide-loop, as shown in Fig. 4. As therein shown, said swivel connection consists of a pin or bolt f, which passes loosely through an aperture in the wall of the guide-loop F and is provided inside of said wall with a head and has screw-threaded engagement with said block F.

The sight-bar A, as herein shown, consists of an upper wall a and side walls a a To the upper wall ais fixed the eyepiece a. The supporting-legs B are pivoted between the side walls of said sight-bar, at the outer ends thereof, by means of pivot-pins a It will be seen that by reason of the pivoted connec-' tion of the legs B with the sight-bar and the pivotal connection thereof at their lower ends with the casing the sight-bar is maintained at all times in a horizontal position when the gun is in position for firing, or, in other words, perpendicular to a vertical plane i11- tersecting the axis of the bore of the gun and the center of the front sight. This is an important feature of my construction, as will hereinafter more fully appear.

H, Figs. 9 and 10, designates a scale-strip which is attached to the upper edge of the rear wall of one of the casings and is preferably arranged obliquely with respect to the vertical and facing toward the rear to permit its being readily seen from the rear by the marksman when using the gun. Said scale is attached to said casing by means of setscrews h, which pass through slots therein, thereby permitting said strip being moved endwise on the casing.

\ Said scale-strip is graduated from the center toward each end thereof, the zero-mark being located at the center of the strip. It will thus be seen that the scale-strip is divided'into two principal divisionsright and left. Each of said principal divisions of said graduating-scale is furthermore subdivided into several subdivisions.

.The guide-loop is provided with a centermark f which cooperates with the scale on said strip and assists the marksman in setting said loop, and thereby the sight-bar, in its proper lateral position. The side wall of the casing adjacent to the screw-shaft G is provided with an annular scale-dial 0?, and the screw-shaft is provided outside of said casing with an-indeX or pointer g, which codperates with said scale. Said scale 0 is used subordinately to the scale on the scale-strip H, and the parts will be desirably so arranged that one rotation of the shaft will move the guideloop F through one subdivision of the scale of the scale-stri p H. The divisions of the scale-dial c are therefore subdivisions of the subdivision of the scale-strip H and enable a lateral adjustment of the sight-bar to be made with greater precision than the same could be made with the use of the scale-strip H alone. .Each subdivision of the scale on the scale-strip H will represent a certain velocity of wind-in miles per hour, (preferably a number of miles,) and the divisions on'the scale-dial 0 will represent subdivisions thereof, each division of said scale-dial desirably representing one mile.

v I designates a spirit-level which is attached to and movable with the horizontal sight-bar A. The said spirit-level is desirably located between the side Walls of the sight-bar, which latter forms, in effect, a protecting-casing for the level. This is a location affording protection for said spirit-level, which is highly desirable when the gun is subjected to severe usage, as is a military gun. As herein shown, the means for attaching the spirit-level to the sight-bar consists of blocks i, provided on their proximate faces with notches which are engaged by the opposite ends of the spiritlevel. One of said blocks is rigidly connected with the upper wall a of the sight-bar by means of a countersunk screw 1" and the other is movably connected with said sightbar by means of an adjusting-screw i Said adjusting-screw has screw-threaded engagement with the block 1', through which it passes, and is immovably connected with the upper wall of the sight-bar and a cross-piece i connected with the lower edges of the side walls. As herein shown, said adjusting screw is passed through said upper wall of the sightbar and said cross-piece and is upset at its lower end to prevent its moving endwise out of place, so that when the screw is rotated it will act by its screw-threaded engagement,

As before stated, the scale-strip H isendwise movable, and a scale 0 is provided below the same on the rear wall of the casing C.

The zero-markv on said scale-strip moves.

across the width of said scale and cooperates with the scale 0". This simple arrangement is designed to adjust the scale-strip in the first instance in a manner to compensate for drift. I When once adjusted, the adjustment will be permanent, and the act of depression and elevation of the sight will move the'same laterally a distance appropriate to the elevation indicated by the elevation-scale to compensate for drift. The rear face of the leg B, adjacent to said scale, as herein shown, is graduated to indicate the required elevation of the sight for different distances and will desirably be graduated to indicate distances of one hundred yards and subdivisions thereof at extreme range.

The operation of a sight mechanism made as thus described is as follows: The sight-bar and eyepiece are shown in Fig. 2 at the normal or point-blank position, and while in this position the center-mark of the guide-block F will be opposite tothe zero-mark of the scale-strip H. In order to compensate for the effect of wind upon the projectile, the marksman will first ascertain the velocity of the wind by any familiar means at hand and will move the guide-loop F laterally by means of the screw-shaft Gin the manner described a distance which is indicated on the windgage scale as appropriate to the said velocity of the wind. At this time the eyepiece is at its point-blank elevation, and when the range is ascertained said eyepiece will be elevated a distance appropriate to' the range by means of the shaft E, the scale on the leg B indieating the amount of elevation required for each one hundred yards or like distance. As the legs B and the sight-bar A are elevated in the manner described the upper ends of said legs and the sight-bar will be moved laterally away from the vertical plane of the axis of the bore of the gun-barrel and the path of movementof said parts will be in a gradually-increasing curved line corresponding with the curvedpath of the projectile, (laterally considered,) due to the effect of the wind on the projectile and the effect of drift. This action is due to the fact that the points of pivot of the legs B move upwardly and in vertical lines while the guide-loop F, connected with one ofthe legs, remains stationary. Owing to gun.

not be necessary in guns used for target pracpins 7', remain vertically stationary.

gun is in position for firing and also the fact that said sight-bar is in a position which is, so to speak, isolated from the other parts of the mechanism, so that it may be readily determined, even without the use of a spiritlevel, when the gun is in an accurate position forfiring by noticing whether or not the sightbar is horizontal. The rear wall of the sightbar is cut away, as shown in Fig. 2, to enable the bubble of the spirit-level to be plainly seen, and thereby enable the same to be kept vertically under the eyepiece when firing the This location of the spirit-level may tiee; but in military and sporting'guns the position is an advantageous one, as it protects the level against injury in the rough usage to which the gun may be subjected.

Next referring to the construction shown in Figs. 12 to 15, both inclusive, it will be noted that the legs B do not pivotally engage the easings C, as in the previous construction. In this construction said legs have sliding engagement with longitudinally-grooved bars J J, which constitute guides therefor. Said bars are pivoted at their lower ends near the lower ends of the casings upon pivot-pinsjj, which are secured in the outer ends of laterally-extending arms J J, affixed to the lockplate. Said pivot-pins may obviously be secured in the rear and front walls of the easings O'and the arms J omitted. The raising and lowering shaft E in this construction is made and arranged the same as in the construction previously described. The grooves in said guide-bars open forwardly, and the teeth I) of the legs B project beyond the forward edges of said bars in position for engagement with the gear sections or sleeves E of the shaft E. The laterally-shiftable block F has swivel connection with a lug J at the upper end of one of the guide-bars, and said block is engaged by the shaft G in the same manner as described in connection with the previous figures, whereby rotation of said shaft laterally shifts the said block and the upper end of the guide-bar, and thereby the sight-bar, with respect to the vertical plane of the bore ofthe gun. The operation of this form of sight mechanism is slightly different from that heretofore described. When the lifting-shaft is rotated in the proper direction, it will act, through the gear sections or sleeves on the shaft and rack-teeth on the legs, to elevate said legs; but the guide-bars J, being fixed at their lower ends to the pivot- The result of this construction is that (the legs constituting in effect rigid extensible parts of the guide-bars) the upper ends of said legs and the attached sight-bar are elevated in an inclined right line instead of in a graduallyincreasing curve, as in the previously-described construction. It will be understood that this angle of deflection of the eyepiece does not accurately correspond with the deflected path of the projectile due to wind and drift, but that the line through which the eyepiece moves approximates the curved path of the projectile. For-ordinary shooting the inaccuracy of this adjustment will be almost inappreciable; but where great accuracy is required it may be effected by a lateral adjustment of the eyepiece through the medium of the screw-shaft G a distance to one or the other side of a point on the scale indicating the known velocity of the wind to compensate for any inaccuracy which may exist.

It has been found that in certain guns the path of the projectile (laterally considered) from the gun to the objective when the objective is beyond a certain distance from the gun does not describe a c0nstantlyincreasing curve throughout its flight. This is true both in respect'to the deviation due to drift and to wind. In such guns it has been found that a portion of the path of the bullet is curved, while another portion thereof more nearly proximates a rightline. In Figs. 16 to 19,inclusive, I have shown a construction which is designed for guns having the peculiarities above mentioned. Said construction is essentiallya combination of the two features herein described and is made as follows: The legs B, connected with the sight-bar A, have sliding engagement with guide-bars K, similar to the guide-bars J. (Shown in Fig. 12.) Said guide-bars K, however, are pivoted at their lower. ends to pivot-pins 7c, which engage guide-slots c in the rear walls of thecasing 0, similar to but shorter than the slots shown in the first-described construction. Said pivotpins project beyond the casing and are provided at their outer ends with thumb-nuts a by which they are locked in place when the sight mechanism has been adjusted as to elevation. The grooves of the guide-bars K,like those of the guide-bars J before described, open forwardly, and the teeth I), connected with the legs B, project outwardly beyond said guide-bars and are adapted for engagement with the gear sections or sleeves E of the shaft E. The guide-bars have interlocking engagement with the loops K, which latter are each connected by a swivel-bolt 7.: with a block K which is engaged by the screw-shaft G, as clearly shown in Fig. 19. The interlocking connection between the loops and bars consists of longitudinal laterally-extending flanges on the bars, forming between the same and the main bodies of the bars longitudinal guide-grooves, within which fit inwardly-directed flanges on the loops, the construction permitting relative longitudinal movement of said parts. The

legs B, which support said sight-bar, fit loosely within the groove of the guide-bars and are held in frictional engagement there with by means of spring as shown in Fig. 17, located adjacent to the upper ends of the guide-bars, interiorly thereof, and engaging said legs B. The legs are provided at their lower ends with enlargements or shoulders M, which prevent the complete accidental withdrawal of the legs from the guide-bars unless sufficient force be exerted by design to overcome the tension of the spring. The operation of this form of sight mechanism is as follows: The lateral adjustment of the sight-bar to compensate for a given velocity of wind is effected by the screw-shaft G in the manner before described. When the shaft E is rotated,it acts by reason of the frictional engagement of the legs B with the guide-bars K to elevate the said guide-bars, together with the legs, until said guide-bars are limited by engagement of the pivot-pins 7a with the upper ends of the guide-slots 0". The effect of this construction is to move the sightbar and the upper ends of the supporting-legs B in a constantly-increasing curved line, the

same as in the construction first described.

After the guide-bars have reached the limit of their movement by reason of the engagement of the pivot-pins 7a with the upper ends of the guide-slots c the action of the mechanism will helike that shown in Figs. 12 to 15-that is to say, the sight-bar will be elevated in a right line instead of in a curved line, owing to the fact that the lower ends of the guidebars are held vertically stationary. In making this form of sight mechanism the slots 0 will be made of such length as to limit the movement of the guide-bars at the time they are elevated sufficiently for the known range at which the path of the projectile (laterally considered) ceases to be a constantly-increasing curved line and approximates a right line, so that the right line through which the sight of the bar moves in the further elevation of the same willcorrespond to the latter part of the path of the projectile. When the sightbar has been moved to the upper limit of its movement and it is desired to depress the same, the guide-bars will be for the first part of the downward movement of said parts locked by the thumb-screw a so that during the first part of the downward movementof the sight-bar it will move in a right line. When the said sight-bar has reached an elevation approximate to the range at which the fiight of the projectile changes from a curved to a substantially right line, the thu nub-screws will be released, so that the further downward movement of the sight-bar will be a curved line. One of said guide-bars K, as shown in Fig. 16, isbroken away or made shorter than the other leg to expose the elevation-scale of the inclosed'leg l3. 7

In applying the device to a gun having no drift provisionwould need to be made for compensating for the effect of wind only, and the eyepiece of the rear sight would be so located that when its center is in the vertical plane of the axis of the bore of the gun the wind-gage scale would register with the indexmark at the zero-point. I I

I do not wish to be limited to the precise construction herein shown, but wish to have included within the spirit of my invention all such constructions as will produce the result herein set forth. v

' I claim as my invention- 1. A rear sight for firearms comprising a horizontal sight-bar which is maintained uniformly perpendicular to the vertical plane which intersects the axis of the bore of the gun and the center of the front sight, means for elevating and depressing said sight-bar,

and means acting on the sight-bar-while being elevated or depressed to shift said bar laterally a distance sufiicient to compensate for the effect of wind upon the projectile at the range appropriate to each and every elevation of the sight.

2. A rear sight for firearms, comprising a horizontal sight-bar which is maintained uni formly perpendicular to the vertical plane which intersects the axis of the bore of the gun and the center of the front sight, means for elevating and depressing said sight-bar and means acting on the sight-bar while being elevated or depressed to shift said bar laterally a distance sufficient to compensate for wind and drift upon the projectile at the range appropriate to each and every elevation of the sight.

3. A rear sight for firearms comprising a horizontal sight-bar, means for elevating and depressing the same, and means acting on said sight-bar'while being elevated or depressed to deflect said sight-bar in a laterally-curved path to correspond with the curved path of the projectile (laterally considered) due to the effect of wind.

if A rear sight for firearms comprising a horizontal sight-bar legs pivoted to the opposite ends of said sight-bar, means for elevating and depressing said legs and bar and shiftable guiding means for said legs.

5; A rear sight for firearms comprising a horizontal sight-bar, legs pivoted to the oppo site ends ofsaid sight-bar, rack-teeth on said legs, a rotative gear engaging said rack and shiftable' guiding means for said legs.

6. A rear sight for firearms comprising a horizontal sight-bar, legs pivoted to the opposite ends of said bar, means for elevating and depressing said legs and the bar and guiding means engaging the upper end of one of the legs said guiding means being adapted to be shifted laterally toward and from the vertical plane of the gun.

7. A rear sight for firearms comprising a horizontal sight-bar, legs pivoted to the opposite ends of said bar, means for elevating and depressing said legs and bar,a laterally-shiftable guide engaging the upper end of one of said legs, and vertical guides controlling the movement of the lower ends of said legs.

8. A rear sight for firearms comprising a horizontal sight-bar, legs pivoted to the oppo IIO site ends of said bar, means for elevating and' depressing said legs and bar, a laterally-shiftable guide engagingthe upper end of one of said legs vertical guides controlling the move mentof the lower ends of said legs, and means for locking said legs in their adjusted positions.

9. A rear sight for firearms comprising a horizontal sight'bar, legs pivoted to the opposite ends of said bar, rack-teeth on said legs, a rotative shaft provided with gear teeth adapted for engagement with said rack-teeth, a shiftable guide engaging the upper end of one of said legs and vertical guides controlling the movement of the lower ends of said legs.

10. A rear sight for firearms comprising a horizontal sight-bar, legs pivoted to the opposite ends of said bar, parallel vertical guides controlling the movement of the lower ends of said-legs a laterally-shiftable guide en gaging the upper end of one of said legs and means for synchronously elevating and depressing said legs.

11. A rear sight for firearms comprising a horizontal sight-bar, legs pivoted to the ends of said bar, and depending on each side of the gun, a casing inclosing the leg on each side of the gun, said casings being provided with parallel guide-slots with which the lower ends of said legs are pivotally connected, a laterally-shiftable guide engaging the upper end of one of. said legs, and means for synchronously elevating and depressing said legs.

12. A rear sight for firearms comprising a sight-bar, means for elevating and depressing the same, and guiding means controlling the movement of said bar while being elevated or depressed which causes said sight-bar in the one part of its upward movement to move laterally in a curved path and in another part of said movement to move laterally in a right line.

13. A rear sight for firearms comprising a horizontal sight-bar, legs pivoted to the opposite ends of said bar, guide-bars engaging said legs which guide-bars are pivoted at their lower ends, and means for elevating and depressing said legs.

14. A rear sight for firearms comprising a horizontal sight-bar, legs pivoted to the opposite ends of said bar, guide-bars engaging said legs which guide-bars are pivoted at their lower ends and have a limited vertical movement, and means for elevating and depressing said legs and sight-bar.

15. A rear sight for firearms comprising a horizontal sightbar, legs pivoted to the opposite ends of said bar, guide-bars which frictionally engage said legs, said guide-bars being pivoted at their lower ends to studs which engage guide-slots which are of less length than the maximum elevation of the sight-bar.

16. A rear sight for firearms comprising a horizontal sight-bar, legs pivoted to the opposite ends of said bar, guide-bars which frictionally engage said legs, said guide-bars being pivoted at their lower ends to studs which engage guide-slots which are of less length than the maximum elevation of the sight-bar, and means for locking said' guide-bars intermediate their limit-s of movement.

17. A rear sight for firearms comprising a horizontal sight-bar which is capable of being elevated and depressed, a spirit-level carried by and movable with said sight-bar and guiding means controlling the movement of said bar while being elevated or depressed which gives lateral movement thereto in a manner to compensate for the efiect of wind upon the path of the projectile at the range appropriate to each and every elevation of the sight.

18. A rear sight for firearms embracing a horizontal sight-bar consisting of connected top, front and rear walls, and spirit-level inclosed between said front and rear walls, said rear wall being cut away at a point opposite to the bubble of the spirit-level.

19. A rear sight for firearms comprising a horizontal sight-bar, legs pivoted to the opposite ends of said bar, means for elevating and depressing said legs and bar, a guide engag ing the upper end of one of said legs, a rotative endwise-immovable screw-shaft, a block having screw-threaded engagement with said shaft, and swivel connections between said block and guide.

. 20. A rear sight for firearms comprising a horizontal sight-bar, legs pivoted to the opposite ends of said bar, means for elevating and depressing said legs and bar, a shiftable guide engaging one of said legs, a wind-gage scale and an index or mark on said leg which 00- operates with said scale, said scale being endwise movable to enable its adjustment to compensate for drift.

In testimony that I claim the foregoing as my invention I affix my signature, in presence of two witnesses, this 7th day of August, A. D. 1899.

EDGAR BRONSON TOLMAN. 

